Abrogation of the oral tolerance to ovalbumin in mice by citrus pectin.
OBJECTIVE
We studied the effects of dietary pectins (citrus pectin [CP] and apple pectin) on oral tolerance in mice.


METHODS
Pectins (1 mg/d) were administered orally for 2 wk. Tolerance was induced with 20 mg of ovalbumin (OVA). Levels of serum antibodies (immunoglobulin [Ig] G, IgG1, IgG2a, IgE) and delayed type hypersensitivity response determined in footpad tests were measured after subcutaneous injection of OVA with complete Freund's adjuvant. Concentrations of immunoreactive OVA in blood were measured by enzyme-linked immunosorbent assay after feeding the animals 20 mg of OVA. Adhesion and cytokine production (tumor necrosis factor-alpha, interferon-gamma) were measured in peritoneal macrophages.


RESULTS
Oral administration of CP was found to prevent the induction of immune hyporesponsiveness induced by OVA feeding. Animals fed OVA and CP were found to produce similar titers of antigen-specific serum IgG and levels of delayed type hypersensitivity response as those animals not fed OVA. CP increased levels of serum IgG1 and IgE. CP was found to enhance the penetration of immunogenic OVA into the serum. CP (1 mg/d) administered orally for 1 wk was also observed to enhance the adhesion and production of cytokines (tumor necrosis factor-alpha, interferon-gamma) in peritoneal macrophages.


CONCLUSIONS
CP administered orally was shown to inhibit oral tolerance. Enhancement of protein antigen penetration to the blood and activation of macrophages were found to precede the inhibitory effect and appeared to mediate it.
Khramova
Daria S
DS
Institute of Physiology, Komi Science Centre, The Urals Branch of the Russian Academy of Sciences, Syktyvkar, Republic of Komi, Russia.
Popov
Sergey V
SV
Golovchenko
Viktoria V
VV
Vityazev
Feodor V
FV
Paderin
Nikita M
NM
Ovodov
Yury S
YS
D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000284:Administration, Oral; D000818:Animals; D002957:Citrus / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007108:Immune Tolerance / Q000187:drug effects* / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007136:Immunoglobulins / Q000032:analysis / Q000276:immunology; D017737:Macrophages, Peritoneal / Q000276:immunology; D027845:Malus / Q000737:chemistry; D051379:Mice; D010047:Ovalbumin / Q000008:administration & dosage / Q000097:blood / Q000276:immunology*; D010368:Pectins / Q000494:pharmacology*
D000276:Adjuvants, Immunologic; D007074:Immunoglobulin G; D007136:Immunoglobulins; D007073:Immunoglobulin E; D010368:Pectins; D010047:Ovalbumin